374 SUMMARY OF CURRENT RESEARCHES RELATING TO 
anterior segment, from wliicli the stem is developed, is smaller, and has 
a smaller nucleus, than the posterior segment from which the root is 
developed. This is probably dependent on the larger requirements for 
nutrition of the latter than of the former segment. 
The same author also records the occurrence of two fully developed 
embryos on a prothallium of Adiantum cuneatum. 
Annulus of the Sporange of Ferns.* * * § — Prof. G. F. Atkinson describes 
in detail the structure of the annulus of the sporange — both the incom- 
plete annulus of the Polypodiaceae and the so-called “ complete ” annulus 
of the other orders. In no cases is it truly complete. In the Cyatheaceae, 
Gleicheniaceae, Hvmenophyllaceae, Schizaeaceae, and Osmundaceae, as well 
as in the Polypodiaceae, the true cells of the annulus are always inter- 
rupted by “ connective ” cells which connect the lip-cells and the 
anterior end of the annulus on the one hand with the pedicel on the 
other. They take no part in the dehiscence of the sporange, but remain 
passive, and thus prevent the rupture of the membrane of the sporange, 
retaining the spores in their place until they are violently scattered by 
the rupture of the annulus. 
Classification of Sigillarieae.f — Herr H. Potonie points out that the 
five groups of Sigillarieae proposed by Weiss, and founded on the sculp- 
turing of the surface of the stem, cannot be retained, since sculpturing 
characteristic of two different groups may be found in the same species, 
and even on different parts of the same specimen. The growth of the 
Sigillarieae, like that of the Cycadeae, appears to have been characterized 
by an alternation of zones of growth. 
Sphenophyllum.f — Fresh observations by M. B. Zeiller confirm his 
view that Sphenophyllum should be constituted into a distinct class of 
Vascular Cryptogams, most nearly allied to the Filicineae, but having 
analogies also with the Marsileaceae and Ophioglossaceae. The species 
appear to have only one kind of sporange ; the sporocarp is a lobe of a 
leaf corresponding to the spike of Ophioglossum or BotrycJiium. 
Muscinese. 
Braithwaite’s British Moss-Flora. — Part xv. of this beautiful work 
includes a description of the remainder of the Bryaceae, and of the whole 
of the Bartramiaceae of the British flora. 38 species of Bryum are 
enumerated. The British representatives of the Bartramiaceae include 
1 species of Conostomum, 5 of Bartramia , 7 of Philonotis , 1 of Breutelia, 
and 1 of Catoscopium. 
’Vegetative Structure of Hepaticae.§ — Prof. K. Goebel describes the 
structure of the auricles and other structures for the collection of water 
in a number of Hepaticae. This purpose is in many cases served by the 
occurrence of lamellae on the leaf, or by its being cut up into linear 
* Bull. Torrey Bot. Club, xx. (1893) pp. 435-7. 
f Gesell. Naturf. Freunde Berlin, Oct. 17, 1893. See Bot. Centralbl., lvii. (1894) 
p. 65. 
X Mem. Soc. Geol. de France, iv. (1893) 39 pp. and 3 pis. See Morot’s Journ. de 
Bot., viii. (1894) Bull. Bibl., p. 111. Cf. this Journal, 1892, p. 827. 
§ Flora, lxxvii. (1893) pp. 423-59 (2 pis. and 18 figs.). 
